Garage door operator



Jan. 19, 1965 H. c. PELTIER 3,

GARAGE DOOR OPERATOR Filed July 18, 1963 3 Sheets-Sheet 1 INVENTOR.

//Me/ (t Par/ 7e Jan. 19, 1965 H. c. PELTIER GARAGE DOOR OPERATOR 3Sheets-Sheet 2 Filed July 18, 1963 N 1 e-a INVENTOR. 6231 4? P5177457?Jan. 19, 1965 H. c. PELTIER 3,

GARAGE DOOR OPERATOR Filed July 18, 1963 3 Sheets-Sheet 5 INVENTOR.

United States Patent 3,166,306 GARAGE DOGR OPERATOR Henry C. Poitier,Hackensack, N31, assiguor to Astrotec, Ina, Garfield, N.J., acorporation of New Jersey Filed July 18, 1963, Ser. No. 295,947 17(Iiaims. (ill. 268-59) This invention relates to a garage door operatorand, more particularly, to a motorized garage door operator whichselectively opens and closes a garage door upon receipt of a signal froma local station or a remote control unit.

It is a primary object of my invention to provide a garage door operatorwhich carries out its normal function of raising and lowering a garagedoor in a new and improved manner and which is particularly suited to beadded to an already existing sectionalized garage door that is mountedfor movement from a closed vertical position to an open overheadhorizontal position and which is hereinafter referred to as an overheadgarage door. My invention is well adapted to be added to a previouslyinstalled overhead garage door which was theretofore only manuallyoperable and which can by the addition of my unit be automated so thatupon the sending of a signal the home owner will without further effortopen or close his garage door.

It is a further object of my invention to provide a garage door operatorof the character described which may be quickly and easily installed ina garage with a minimum expenditure of elfort and funds and which may beinstalled by a relatively unskilled worker following a simple set ofdirections. My garage door operator is characterized by its simplicityof installation. No large beam members or other complex or cumbersomeparts need be added to an already existing overhead garage door. Rather,by the simple addition of a drive assembly and guide cables, my garagedoor operator may be made a permanent part of a garage in a matter ofhours with the use of only simple handymans tools.

It is a further object of my invention to provide a garage door operatorof the character described which is particularly adapted forinstallation in garages wherein there is a minimum of space between thegarage door in its open condition and the ceiling of the garage, only afew inches of clearance being needed for the installation of myoperator. Other garage door operators of which I am aware requireconsiderable head room for their installation and operation. That is tosay, beams and sprockets chains and other apparatus are commonlynecessary and must be installed and located in the space between thegarage door in its open position and the ceiling of the garage. Thislimitation has made it extremely difiicult and often impossible toinstall a garage door operator in a garage which has not been especiallyconstructed to allow sufficient clearance space for a garage dooroperator. Further, it should be noted that low ceiling garages are quitepopular today and thus there exists a great number of such garageswherein a minimum, i.e. less than half a foot, of space exists betweenthe open garage door and the garage ceiling.

It is yet another object of my invention to provide a garage dooroperator of the character described which is rugged and foolproof in useand yet is economical in manufacture and assembly.

I further desire that my garage door operator be so constructed so thatshould for some unusual reason, as a motor failure, the operator becomejammed, I may by release means quickly disengage my garage door operatorso that the garage door can be manually opened or 3,166,305 PatentedJan. 19, 1965 closed and appropriate repair and maintenance services maybe performed.

These and various other objects and advantages of my invention willbecome apparent to the reader in the following description.

My invention accordingly consists in the features of construction,combinations of elements and arrangements of parts which will beexemplified in the device hereinafter described and of which the scopeof application will be indicated in the appended claims.

In the accompanying drawings in which is shown one of the variouspossible embodiments of my invention,

FIG. 1 is a perspective view of the interior of a garage with my garagedoor operator properly installed;

FIG. 2 is a front elevational view of the drive assembly of my garagedoor operator, the drive assembly takingthe illustrated posture when thegarage door is in its closed position;

FIG. 3 is a side view of the drive assembly in the position shown inFIG. 2;

FIG. 4 is a side view of the drive assembly in the posture which ittakes when the garage door is approaching its open terminal position;

FIG. 5 is an enlarged fragmentary side cross-sectional view of the driveunit taken substantially along the line 5-5 of FIG. 2 but illustratingthe drive assembly in its horizontal terminal position;

FIGS. 6 and 7 are fragmentary side cross-sectional views of the driveassembly illustrating the follower means approaching a horizontalterminal position, and in a vertical terminal position, respectively;

FIGS. 8 and 9 are fragmentary perspective views, respectively, of theend portion of .a guide track, and an impact buffer within the track;

FIG. 10 is a perspective view'of the guide bracket for the main cable;

FIG. 11 is a perspective view of the cross-cable yoke; and

FIGS. 12 and 13 are, respectively, plan and side views of thequick-release extendible coupling.

Referring now in detail to the drawings, the reference numeral 10denotes an overhead garage door of a conventional type. The door 10moves from one terminal position (shown in FIG. 1) in which it issubstantially vertical and in which it closes the entrance to the garageto another terminal position in which it is overhead and horizontal andin which latter position the entrance to the garage is open. Dual trackmeans 12 guide and support the garage door 10 in its movement betweenits closed terminal position and its open terminal position. Each ofsaid dual track means 12 comprises an inwardly opening track 14 (seeFIGS. 8 and 9) which is C-shaped in cross-section. Flanged rollers 16are rotatably joined to the vertical side edges of the door 10 at thejunction between the sections of the garage door and at the top andbottom of the door. Said rollers are captively held within the C-shapedsection of the tracks 14. As the garage door 10 moves between itsterminal positions the rollers 16 roll along and within their afiiliatedtracks 14 and the sections of the door'10 swing so as to allow thegarage door to shift as desired between an open and closed position. Thesectionalized garage door 10, the track means 12 and the rollers 16 areentirely conventional and are well known to those skilled in the art.The garage door operator to be described may be installed concurrentlywith the erection of the garage or may be added to any conventionalpreexisting garage having an overhead door.

The garage door 10, mounted for movement between its open and closedpositions, is automated by a garage door operator generally designatedby the reference numeral, 18. Said garage door operator includes a driveassembly which is attached to the garage door Ill at the top edgethereof and is centered between the side edges of the garage door. Thedrive assembly 20 includes an electrical motor 22 which is energized byappropriate and well known circuit means including a supply cable 23.The electric circuit means is preferably of the type which is energizedby an outside source of electrical energy, e.g. electrical power lines,and in response to a radio signal or key or push button signal given bythe homeowner. The electric motor 22 as well as the other components ofthe drive assembly 26 are mounted on the door 10 by a support plate 24which is a heavy metallic flatmember having spaced apertures 26throughwhich screws 28 pass and attach the plate to the garage door 10. The topof the support plate 24 has integral with it a flange 30 which extendsat a right angle to'the plate 24 and which overlies the top edge of thegarage door 10.

The drive assembly 2% by virtue of the position of the support plate 24is located directly on the garage door 10 at the top central portionthereof. The motor 22 is carried by a casing 32 which is joined to thesupport plate 24, as by welding. The casing 32 rotatably mounts a shaft34 of a traction drive wheel 36. Both ends of the shaft 34 project fromdifferent sides of the casing 32 and the shaft 34 is mounted in ahorizontal position and parallel to the curved plane in which the garagedoor 10 moves. The motor 22 by an appropriate gear reduction mechanismwithin the casing 32 drives the shaft 34 and thus the traction drivewheel 36 which is fast thereon. The circumference of the traction wheel36 includes two circumferential flanges 33 which define therebetween asemicircular peripheral groove 40. The surface of the groove 40 ispreferably composed of a friction inducing material such as semi-hardrubber.

The drive assembly 20 further includes plural idler wheels, respectivelya first idler wheel 42 and a second idler wheel 44. The idler wheels 3244 are fast on different freely rotatable shafts, respectively 48, 46,the shafts being carried by U-shaped back-to-back brackets,respectively, 50, 52 the bottom brackets 52 being joined as by Weldingto the casing 32. The shafts of the idler Wheels 42, 44 and the shaft 34of the traction drive wheel 36 are parallel to one another. As seen inFIG. 3, when the door 10 is in its closed terminal position, the axis ofrotation of the idler-wheel 42 is located above the axis of rotation ofthe traction drive wheel 36 and the axis of rotation of the second idlerwheel 44 islocated above and forwardly of the axis of rotation of thetraction wheel 36 and also forwardly of the axis of rotation of theidler wheel 42. The idler wheels 42, 44 have grooves on their outerperipheries of the same contour and dimension as those of the tractionwheel 36; however the idler wheels are of somewhat smaller diameter thanthe traction drive wheel.

A strong elongated flexible element, e.g. a main cable 54 of a Woundwire type, is horizontally disposed, is located above the garage doorll) in both its closed and open positions and runs from the front to therear of the garage. The main cable 54 is fixed at both of its ends andis located centrally between the tracks 14. A

portion of said cable 54 (dependent on the location of the garage door)'is engaged by the wheels of the drive assembly 20. More specifically,the cable 54 passes clockwise (going from rear to front) around thefirst idler 42 (as seen in FIG. 3) and engages a portion of itsperiphery which faces the second idler wheel 44. The cable then passescounterclockwise around the traction drive wheel 36 and then clockwisearound the other idler wheel 44. The cable 54 is thereby entrained aboutand frictionally gripped by the wheels and the idler wheels are soplaced that more than one-half of the circumference of the tractiondrive wheel 36 is in contact with the cable.

Follower means 56 is carried by the drive assembly 2t and is guided bythe cable 54 throughout the movement of the garage door 10 between itsclosed and its open terminal positions. To this end the follower means56 is mounted for rotation relative to the garage door 10 about an axiswhich is horizontal and parallel to the axes of rotation of the tractionand idler wheels. Said follower means 56 comprises an elongated stiflhollow rod 58 which is rectangular in cross-section and open at bothends. The rod 58 includes two parallel horizontally aligned coextensiveslots 60 of uniform width located in opposed vertical walls of the rodin the forward portion thereof adjacent the drive assembly 20. One endof the shaft 48 of. the upper idler wheel 42 external to the bracket 5tpasses through both of these slots 60. The follower means 56 by virtueof the aforesaid shaft 48 and slots 60 in the rod 58 is mounted forrotation about the axis of the shaft 48 relative to the garage door it).The rearward end of the rod 58 carriers an eye bolt 62 having anelongated shaft 64 which passes diagonally through the rod 58 and whichis joined thereto as by nuts 66 disposed on the shaft 64 againstopposite corners of the rod. 58 through which the bolt passes. The cable54 is threaded through the eye 68 of the bolt 62.

The follower means 56 is mounted for movement relative to the driveassembly alonga second axis, this axis being the axis of symmetry of therod 58 which is parallel to the reach of the cable 54. The slots 6t) areslightly larger than the diameter of the shaft 43 so that the rod mayshift axially forwardly or rearwardly with respect to the shaft 48 aswell as rotate about this shaft.

Biasing means urges the rod 58 rearwardly with respect to the shaft 48.For this purpose an elongated helical compression spring 7% is captivelyheld within the hollow rod 58, the spring being abutted on one end bytheshaft 64 of the eye bolt 62 and on the other end by the shaft 48. Thecoil spring 70 is under compression so as to urge the rod 53 rearwardly,i.e. away from the shaft 43. That is to say, the end of the rod 58distant from the eye bolt 62 is biased toward the shaft 48.

Switch means responsive to the follower means 56 as garage door Itapproaches either of its terminal positions deenergizes the driveassembly when the switch means is actuated upon the arrival of the doorat either of such positions. Said switch means comprises a momentarysnap switch 72 such as a Micro switch or a Mu switch attached to theoutside of the bracket 52. The body of the snap switch 72 carries anactuating button '74 which is spring biased outwardly and a pivotallymounted actuating lever 76. The actuating lever 76 is so positioned thatit overlies the actuating button 74 and so that rotation of the lever 76toward the switch body depresses the button 74 so as to actuate the snapswitch 72 and thereby deenergize the motor 22 which has been moving thegarage door. In a position of repose the lever 76 permits the button 74to be spring biased to unactuated position. Upon depression of the lever76, the button 74 is correspondingly depressed into the housing of thesnap switch to cut 0E power to the motor. Theend of the lever 76 distantfrom the pivotal end rotatably mounts a small roller 78, this beingprovided so that a body (the end of the rod 58) contacting the lever 76if caused to strike the roller 78, will slide thereon.

7 Stop means are fast to the cable $4 at arearward portion thereof. Saidmeans constitutes an apertured disc 8!} encircling the cable 54 andfrictionally joined thereto as by a radially inwardly protruding setscrew 82. The

diameter of the disc 80 is larger than that of the aperture of the eye68 of the eye bolt 62 so that the disc 8% cannot pass through the eye.

The shaft 48 and the switch 72 are so mutuaily located that bothrotativemovement and axial movement of the rod 58 will cause depressionof the actuating lever 76. As shown in FIGS. 5 and 6, when the rod 58strikes the disc 8t and is caused thereby to translate axially andforwardly relative to the door and drive assembly, the end of the rod 58adjacent the drive assembly 20 travels forwardly in a straight lineintersecting the lever 76. During such straight line forward travel therod strikes the lever near its pivoted end and forces the lever todepress the button 74. Rotative movement of the rod 58 about the shaft48 as the door approaches its closed position causes one side of the rodto swing against the actuating lever roller 78 (see FIGS. 3 and 7) againforcing the lever 76 to depress the button 74 and shut off the motor. Ascrew 81 extends from the bracket 58 and acts as a stop to limit the rod58 in its rotative actuating movement.

When the rod 58 by axial or rotative motion strikes the lever 76, thefollower means has assumed an operative location. This happens when thegarage door has reached either of its terminal positions. The switchmeans is responsive to the follower means in both of these locations todeenergize the drive assembly. The spring 78 urges the follower means 56away from the lever 76 and to an inoperative location.

As has been previously mentioned, the cable 54 is fixed at both of itsends. For the front end, a guide bracket 84 is attached to a portion ofthe garage door frame centrally and immediately above the garage doorentrance between the tracks 14. The bracket 84 includes a flat heavyrigid plate 85 which is joined, as by screws 86, to the frame of thegarage door. The bracket 84 further includes an arm 88 pivoted at oneend on the plate 85, as by a rivet 98 which passes through the lever andthe plate 85. The arm is mounted for limited rotation in a planeparallel to the plane in which the plate 85 lies. from the plate 85 andhas its legs joined, as by welding, to the top and bottom edges of theplate. The bail 92 spans a central portion of the arm 88 near andparallel to the plate 85 so as to relieve pressure on this rivet 90 whenthe garage door operator is in motion. The legs of the bail limit upwardand downward rotational movement of the arm. The other end of the arm 88is angularly oifset and apertured. The cable 54 passes throughthe'aperture in the arm 88, making a right angled bend and then beingjoined to one end of a strong elongated helical tension spring 94. Theother end of the spring 94 is attached, as by a screw 96, to the frameof the garage door 10. The spring 94 maintains the cable 54 in tension.

An elongated flexible element, a cross-cable 98 carries the other end ofthe main cable 54. Thecross-cable 98 runs from one side of the garage tothe other and is disposed between the ends of the tracks 14. Thecrosscable 98 is horizontal and approximately perpendicular to the maincable. A central portion of the cross-cable 98 supports the rear end ofthe main cable 54 (see FIG. 1). A hollow self-centering tubular yoke 100is disposed about the central portion of the cross-table 98 and is ofsufiicient internal diameter so as to be able to slide, i.e. ride alongthe cross-cable. One side of an S-shaped hook 102 is joined to the yoke100 as by welding. The other side of the hook 182 is joined to the rearend of the cable 54 and passes through a loop in the cable formed by aconventional anchor clamp 104. When the main cable is under tension theyoke will slide along the crosscable until it reaches approximately acentral location thereon.

Impact buffers 186 are carried within the C-shaped channel formed ineach of the tracks 14 at a rearward portion thereof (see FIG. 9). Bothbuffers are identical and only one will be described. The impact buffer186 is held by a multi-apertured length of. rigid angle-iron 188, theangle-iron fitting within the channel-shaped opening of the track 14.The apertures 118 in the angle-iron are disposed in a row parallel tothe length of the track 14 and are provided so that the impact buffer106 can be positioned at any spot at the rear end of the track 14 as bya bolt 105 which passes through an aperture in the A U-shaped bail 92has its central portion spaced track 14 and an aligned aperture 110 inthe angle-iron 108. (See FIG. 8.) Each bulfer 106 comprises a verticalcarrier plate 112 secured to the front end of its afliliated angle-ironand having a central through bore 114 about which is disposed a collar116 that is integral with the plate 112. An elongated shaft 118 passesthrough the bore 114, the collar 116 effectively prohibiting sidewiseroofing movement of the shaft. The shaft 118 has a head 120 on itsrearward end. The front end of the shaft 118 is enlarged as by a hardrubber cap 122 which is disposed over and frictionally grips said end ofthe shaft. A helical compression spring 124 is wound about the shaft 118and is disposed between the plate 112 and the cap 122. The spring 124resists rearward movement of the shaft 118.

An apertured ceiling hanger 126 is joined to the end of track 14 by thebolt 105 and serves to suspend the track means 12.

Each end of the cross-cable 98 is held under tension by an elongated eyebolt 128 which also protrudes through an aperture 110 in the angle-iron108. (See FIG. 8.) A loop formed in the end of the cross-cable 98 by useof a conventional anchor clamp 130 passes through the eye 132 of the eyebolt 128. The eye bolt has an elongated shank 134 which extends throughan angle-iron aperture 110 and has a tapped end distant from its eye132. A nut 136 is screwed onto this end, and a helical compressionspring 138, disposed about the shank 134 between the angle-iron 108 andthe nut 136, urges the eye bolt 128 outwardly through the angle iron andthus tensions the cross-cable 98 and, in turn, the main cable 54.

Quick release extendible coupling means is provided to permit fastmanual loosening of the cross-cable 98 so that the main cable 54 may berelaxed to an extent sufficient to free the main cable from the driveassembly 20. This may be necessary when for some unusual reason thegarage door operator becomes jammed as by failure of the motor 22. Saidquick release means comprises a quick release coupling 140 whichinterrupts the cross-cable 98 adjacent one end thereof. The coupling 140carries a hook 142 on one side which passes through a loop formed in thecross-cable 98 by an anchor clamp 144. The hook 142 has one longer legrotatably joined to the cross-bar of a yoke 146, the yoke legs 148extending away from and generally parallel to the longer leg of the hook142. An elongated downwardly sloping handle 150 which has a bifurcatedend 152 is rotatably mounted at the beginning of its bifurcated portionbetween the tips of the yoke legs 148 by pins 154 passing throughaligned apertures in the adjacent yoke legs and the bifurcated end 152.Another hook 158 has one end extending through a loop in the cross-cable98 formed by an anchor clamp 160. The other end of the hook 158 is aneye 162 through which passes a pin 164 mounted between the ends of thebifurcated portion 152. When in a contracted position, and when there istension on both sides of the coupling 140 at the hooks 142, 158, the pin164 is pulled downwardly to the left (as viewed in FIG. 13) and belowthe pins 154 by force along the long reach of the hook 158. The pin 164moves downwardly until the handle 150 rotating clockwise abuts the hook158 thus locking the coupling in contracted position. When it is desiredto expand the coupling 140 and thus slacken the cross-cable 98, thehandle 150 is pulled downwardly in the direction indicated by the arrowA. The handle will rotate on the pins 154, the bifurcated end 152thereby rotating with the handle in a counterclockwise direction acrossdead-center and then to a position on the other side of the pins 154.The distance between the hooks 142, 158 will thereby be greatlyenlarged, thus slackening in the cross-cable 98.

When the garage door 10 is closed, the position of the drive assembly 20relative to the garage door is as shown in FIG. 3. The follower means 56is substantially horizontal (as it always is) and is perpendicular tothe garage door 18, being held in this position by the eye bolt 62 whichis supported by the drive cable 54. Uponacontrol signal given by thehomeowner, the drive assembly 2% is energized causing the electric motor22 to drive the trac tion drive wheel 36 in a counterclockwise directionas seen in FIG. 3. The drive assembly 21) will thereby exert first anupward and then rearward force on the garage door 10 so that the doorwill move along the tracks 14.

As the garage door 10 moves from its closed terminal position toward itsopen position, it swings from the vertical to the horizontal. Thefollower means 56, being rotatably mounted about the shaft 48 andsliding along the main cable 54, remains in a substantially constantattitude relative to the main oable.

FIGS; 4 and 6 illustrate the position of the follower means 56 as itapproaches its horizontal terminal (open) position. The door 10 inmoving between its terminal positions has rotated 90 with respect to theconstant attitude follower means.

FIG. shows the position of the follower means 55 at its horizontalterminal position. The eye bolt 62 has struck the disc 80 fixed on thecable 54 andthereby the rod 58 has been forced axially forwardly(relative to the rearwardly moving door) against the force of the coilspring 70 so that its forward end struck the actuating lever 76. This inturn forced the lever to depress the actuating button 74 and caused thesnap switch 72 to deenergize the drive assembly 20. The position of theactuating lever immediately prior to its operative engagement by the rod58 is illustrated in dot-and-dash lines in FIG. 5.

The impact buffers 106 are located in the tracks 14 in a position suchthat the top edge of the garage door reaches the buffers shortly beforethe eye bolt 62 strikes the disc 80. The top edge of the garage door 16strikes the fronts of the caps 122 moving the shafts 118 rearwardly sothat the coil springs 1.24 are compressed. The impact buffers 106restrain and inhibit movement of the garage door beyond a predeterminedlocation and prevent the disc 80 from absorbing the heavy momentum ofthe moving garage door.

When-the homeowner wishes to close his garage door he gives a controlsignal that actuates the electric motor 22 in a reverse direction. Themotor then rotates the traction drive wheel 36 in a clockwise directionas shown in FIG. 4 and the drive assembly 20 begins to move the garagedoor back forwardly along the cable 54 and down to its vertical closedposition. Immediately afterleaving its horizontal terminal position thecoil spring 70 moves the rod 58 rearwardly and away from the actuatinglever 76 until the ends of the slots 60 abut the shaft 48. This positionis shown in FIG. 6. The drive assembly 26 continues to move the garagedoor It? along the tracks 14 and back to its vertical terminal position,and, as the garage door swings and this position is approached, thefollower means 56 rotates relative to the garage door It) about theshaft 48. A 90 rotation takes place and as the garagedoor approaches itsclosed terminal position the rod 58 swings against the roller 7% mountedon the actuating lever '76. This abutment again causes depression of theactuating button 74 so that the drive assembly 2t? isdeenergized.

a The bracket-84 allows limited rotation of the arm 83 andhence limitedupward and downward movement of the main cable 54 so as to adjust forthe rise and drop in the drive assembly 29 as it moves around the bendIt will now be evident toa reader of the instant dis closure that theseveral objects of my.invention have been attained. My garage door maybe quickly and easily installed by simple attachment of the supportplate 24 to the top edge of the garagedoor wand the proper location andinstallation of the main cable 54 and the cross-cable 98. No heavy,cumbersome or complex parts need be installed and the installationpreviously de scribed may be accomplished through the use of handymanstools. The pie-existing track structure of the garage door'is retainedso that no additional heavy supporting members are called for.

As shown in FIG. 3 the height of my garage door op erator is only a fewinches higher than the garage door when the garage door is in its closedposition. When the garage door is in'a horizontal position, as shown inFIG. 4-, the garage door operator extends barely more than a cableswidth over the garage door. Attention also is called to the location ofthe idler wheel 44 which is such that the reach of the cable extendingtherefrom forwardly is clear of the top surface of the garage door.

It thus will be seen that I have provided a device which achieves theseveral objects of my invention and which is well adapted to meet theconditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment set forth, it isto be understood that all matter herein described or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent,

1. A motorized garage door operator for selectively opening and closinga sectionalized overhead garage door supported and guided by dual trackmeans for shifting the garage door between a closed vertical terminalposition and an overhead open horizontal terminal position, said garagedoor operator comprising a horizontal central front-to-rear flexibleelongated element fixed at its ends and located above the garage door, adrive assemly mounted on the door adjacent the top edge thereof, saiddrive assembly including traction means operatively engaging theelongated element for reversible movement therealong, follower meansmounted for rotational movement about an axis relative to the garagedoor, said follower means being guided by the elongated element andthereby swinging to an operative location when the garage doorapproaches its closed vertical terminal position, said follower meansbeing further mounted for movement along a different axis and movingalong said axis to an operative location when the garage door approachesits open horizontal terminal position, means for energizing the driveassembly, and switch means carried by the garage door and mechanicallyresponsive to the follower means to deenergize the drive assembly onlywhen the follower means assumes either of its operative locations.

2. A motorized garage door operator as set forth in claim 1 wherein theaxes with respect to which the follower means is mounted are transverseto one another.

3. A motorized garage door operator as set forth in claim 1 wherein therotational axis of the follower means is horizontal and parallel to theplane of the garage door and the second-named follower means axis isparallel to the elongated element.

4. A motorized garage door operator for selectively opening and closinga sectionalized overhead garage door supported and guided by dual trackmeans for shifting the garage door between a closed vertical terminalposition and an overhead open horizontal terminal position, said garagedoor operator comprising a horizontal central front-to-rear flexibleelongated element fixed at its ends and located above the garage door, adrive assembly mounted on the door adjacent the top edge thereof, saiddrive assembly including traction means operatively V engaging theelongated element for reversible movement therealong, follower meansmounted for rotational movement relative to the garage door about ahorizontal axis parallel to theplane of the garage door and swinging toan operative location when the garage door approaches its closedvertical terminal position, said follower means slidably riding alongthe elongated element and maintaining a substantially constant attitudealong a second axis parallel to the elongated element as the garage doormoves between its terminal positions, said follower means being furthermounted for reciprocal movement along the second axis, stop means joinedto the cable at a rear portion thereof and abuttingand thereby movingsaid follower means along its second axis to an operative location whenthe garage door approaches its open terminal position, means forenergizing the drive assembly, and switch means carried by the garagedoor andmechanically responsive to the follower means to deenergize thedrive assembly only when the follower means assumes either of itsoperative locations.

5. A motorized garage door operator as set forth in claim 4 whereinbiasing means urges the follower means along the second axis and to aninoperative location.

6. A motorized garage door operator as set forth in claim 4 wherein thefollower means swings through an arc of 90 between its operativelocations.

7. A motorized garage door operator as set forth in claim 4 wherein theelongated element is fixed at its rear end by an elongated side-to-sidehorizontal flexible crosselement, said first named element being ridablealong a central portion of the cross-element.

8. A motorized garage door operator as set forth in claim 7 whereinbiasing means joins each of the ends of the cross-element to a differenttrack means, said biasing means holding said cross-element in tension.

9. A motorized garage door operator as set forth in claim 7 wherein aquick-release mechanism selectively slackens the elongated elementswhereby to selectively release the garage door operator.

10. A motorized garage door operator as set forth in claim 4 wherein thedrive assembly is joined directly to the top edge of the garage door andwherein said drive assembly includes a motor, a traction wheel driven bythe motor and plural idler wheels, all of said wheels being.

mounted for rotation about parallel axes and frictionally entraining theelongated element and being located so that when the garage door is inits, closed vertical position the axes of the idler wheels are above andrearward of the axis of the traction wheel.

11. A motorized garage door operator as set forth in claim 10 whereinthe rotational axis of the follower means is coincident with the axis ofrotation of one of the idler wheels.

12. A motorized garage door operator as set forth in claim 4 wherein theelongated element is fixed on its front end by a bracket arranged toconstrain the front end of the cable for limited vertical movement.

13. A motorized garage door operator as set forth in claim 4 wherein aspring-loaded impact buffer is carried by each of the track means andabuts the top edge of the door so as to slow and restrain movement ofthe garage door shortly before the door reaches its horizontal openterminal position.

14. A motorized garage door operator for selectively opening and closinga sectionalized overhead garage door supported and guided by dual trackmeans for shifting the garage door between a closed vertical terminalposition and an overhead open horizontal terminal position, said garagedoor operator comprising a horizontal central front-to-"ear flexibleelongated element located above the garage door and supported at itsforward end, a drive as sembly mounted on the door adjacent the top edgethereof, said drive assembly including traction means operativelyengaging the elongated element for reversible movement therealong, anelongated side-to-side horizontal flexible cross-element having acentral portion carrying the rear end of the first named element, andmeans tensioning the said first named element.

15. A motorized garage door operator as set forth in claim 14 whereinbiasing means urges the ends of the cross-element apart so as to holdsaid cross-element in tension.

16. A motorized garage door operator as set forth in claim 14 wherein amember is joined to the rear end of the first named element and slidablyrides along the crosselement.

17. A motorized garage door operator as set forth in claim 14 wherein amember is joined to the rear end of the first named element and slidablyrides along the crosselement and a bracket supports and constrains thefront end of the element for limited vertical movement.

References Cited in the file of this patent UNITED STATES PATENTS2,703,236 Verdier d. Mar. 1, 1955

1. A MOTORIZED GARAGE DOOR OPERATOR FOR SELECTIVELY OPENING AND CLOSINGA SECTIONALIZED OVERHEAD GARAGE DOOR SUPPORTED AND GUIDED BY DUAL TRACKMEANS FOR SHIFTING THE GARAGE DOOR BETWEEN A CLOSED VERTICAL TERMINALPOSITION AND AN OVERHEAD OPEN HORIZONTAL TERMINAL POSITION, SAID GARAGEDOOR OPERATOR COMPRISING A HORIZONTAL CENTRAL FRONT-TO-REAR FLEXIBLEELONGATED ELEMENT FIXED AT ITS ENDS AND LOCATED ABOVE THE GARAGE DOOR, ADRIVE ASSEMBLY MOUNTED ON THE DOOR ADJACENT THE TOP EDGE THEREOF, SAIDDRIVE ASSEMBLY INCLUDING TRACTION MEANS OPERATIVELY ENGAGING THEELONGATED ELEMENT FOR REVERSIBLE MOVEMENT THEREALONG, FOLLOWER MEANSMOUNTED FOR ROTATIONAL MOVEMENT ABOUT AN AXIS RELATIVE TO THE GARAGEDOOR, SAID FOLLOWER MEANS BEING GUIDED BY THE ELONGATED ELEMENT ANDTHEREBY SWINGING TO AN OPERATIVE LOCATION WHEN THE GARAGE DOORAPPROACHES ITS CLOSED VERTICAL TERMINAL POSITION, SAID FOLLOWER MEANSBEING FURHTER MOUNTED FOR MOVEMENT ALONG A DIFFERENT AXIS AND MOVINGALONG SAID AXIS TO AN OPERATIVE LOCATION WHEN THE GARAGE DOOR APPROACHESITS OPEN HORIZONTAL TERMINAL POSITION, MEANS FOR ENERGIZING THE DRIVEASSEMBLY, AND SWITCH MEANS CARRIED BY THE GARAGE DOOR AND MECHANICALLYRESPONSIVE TO THE FOLLOWER MEANS TO DEENERGIZE THE DRIVE ASSEMBLY ONLYWHEN THE FOLLOWER MEANS ASSUMES EITHER OF ITS OPERATIVE LOCATIONS.